I've seen some aggression from the six line towards the scooter blenny, but no stress has aroused from "scoots". But if a 1" six line can kill off my 6" tang because he runs him out of the tank, I dont think it was meant to be for the tang! I watched that tang think that my coral banded shrimp would clean him and have actually seen the banded shrimp latch on to the tangs lip thinking it was going to take him down and the tang just does a quick flip of his fins and he is gone, but its back in about 5 minutes thinking he'll clean him again!